Finding a fit for foliar fertilization in your application program can be a good way to put more acres under a high-clearance sprayer. It can also be another way to add value to your relationship with your growers. However, the concept remains a contentious issue with claims and counter claims, even with nitrogen-based products in crops where their value is proven.

One problem that has plagued foliar application acceptance is positioning of foliar as a replacement for preplant or side-dressing without consistent data to back it up. Another problem is the difficulty of collecting independent, reliable data. Unfortunately, such data is increasingly unlikely to surface as Extension research budgets and personnel continue to be cut. However, even without those constraints, trade secrets limit what research can be revealed.

"Foliar fertilizer products, unlike pesticides, don't have to go through a permitting process; they simply have to list their analysis," said Bryan Young, agronomist, Southern Illinois University, Carbondale. "Additives and formulations are all proprietary. We are never going to find out what the true chemistry and science is behind a particular product, and to do valid research, you need to understand those things. Only then can you identify what component is actually having an impact."

What Young and others like Kelly Nelson, research associate professor, Greenley Research Center, Novelty, Mo., are left to do is run comparison trials. Both recently took part in a three-state study with 22 comparison trials. The plots showed an average increase of 10 bushels per acre with a one gallon per acre rate of Nitamin 30L from Georgia-Pacific applied with a labeled rate of Headline fungicide. In Missouri, the fertilizer alone applied at tassel jacked yields from 15 to 28 bushels per acre over controls. The combination of foliar fertilizer and fungicide produced yield increases of 23 bushels per acre in 2008 and 27 bushels per acre in 2009.

No Blanket Recommendations
Are those results enough to justify recommending customers use foliar as a partial replacement for a base program? Not according to the two researchers. However, they do point to benefits possible from using foliar when it is carefully targeted to a specific need. That is especially true of combination programs, such as in the Georgia-Pacific study, where the cost of the trip can be shared between a crop protectant and the crop nutrient. Even then, questions need to be answered, said Nelson.

"We need to understand when foliar is needed, why it is needed and what is the expected response," he said. "We have to be able to justify the added expense. If it's not needed, don't do it."

When foliar N is needed, it can be money in the bank for the customer with or without a companion product, suggested Greg Pirak, owner and operator of Valley Ag Supply, Gayville, S.D. This past season, foliar-applied N helped him rescue a customer's corn.

"We had corn in a real N-deficient state due to cool, wet soils," recalled Pirak. "We put a 33 percent slow release N on at one to two gallons per acre. It really turned the crop around and had it growing again with active photosynthesis and absolutely no burn."

Foliar For Special Conditions
It is just such special conditions that Nelson and Young endorse for foliar targeting. "This past season was an ideal opportunity for foliar applications early or mid-season as our corn struggled to find the nitrogen it needed," said Young. "Wet weather reduced nitrogen availability to the crop, and persistent rains prevented side-dressing in some areas."

Young said growers and their retailers in his area did make rescue foliar applications this year. He is looking forward to reviewing crop response and, of course, cost. He sees economics entwined with efficacy. Even where foliar has produced a positive response, how effective the product is and why it is effective remain key questions.

"Full-service retailers have lots of opportunities to match potential benefits to a particular grower and his management style or system," said Young. "We aren't at a point where we can say this formulation or product works better or best. What works depends on individual growers, growing conditions and what they want from the application. Retailers need to evaluate the product claims and ask for data to back them up so they can advise their growers."

It is in that grower-specific application that Tim Criddle, director of marketing, Miller St. Nazianz Inc., sees a tremendous opportunity for retailers. He acknowledged that ongoing farm consolidation is encouraging more and more large growers to buy applicators from Miller and others. He noted that a growing number of Miller customers are using the applicators for top dressing with liquid N, as well as for weed or pest control. Foliar is a natural extension of that program for retailers and growers who own their own sprayers, if they are self-propelled, high-clearance models such as the Miller Nitro, suggested Criddle.

"They can put on enough starter to get the crop growing properly and then react to growing conditions, whether drought, high moisture or ideal conditions, and give the crop the extra nutrients needed to reach their full potential," he said. "With a high-clearance sprayer, they can come back throughout the season with foliar applications of N while they are making other pesticide applications."

Additional Use of Sprayers
Criddle pointed out that not every sprayer is designed for foliar applications. The Miller Nitro was introduced specifically for foliar use with its size (up to 1,600 gallons), clearance (72 inches) and stainless steel and treated components.

"You need a sprayer that can enter the field at any time, including late season, with high-volume, high flow rates and stand up to the corrosive effects of fertilizers," said Criddle. "Only then do you have a true opportunity to manage input costs with time-critical applications for maximum return on investment."

He adds that for those retailers who make the investment, it is another service to offer customers. To those whose customers make the investment, helping them make best use of the equipment opens the door to a strong customer relationship.

"If a retailer wants to supply farm inputs to these large-scale farmers, they need to become true agronomic partners and drive the bottom line return on investment," said Criddle. "Foliar programs have to be tied to sound agri-management. If their retailer helps them set up a program that manages input costs and maximizes yield, they will be customers for life."